U.S. patent number 3,823,808 [Application Number 05/132,057] was granted by the patent office on 1974-07-16 for tape cartridge provided with a display portion.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Takayoshi Hanagata, Minoru Murata, Tatsuo Nishikawa.
United States Patent |
3,823,808 |
Murata , et al. |
July 16, 1974 |
TAPE CARTRIDGE PROVIDED WITH A DISPLAY PORTION
Abstract
A tape cartridge containing therein a printing tape for use with
a compact electronic computer. The tape may readily be set with
respect to the computer body, and printing may be effected on the
tape at an exposed portion of the cartridge by the printing device
of the computer and information so printed on the tape may be
viewed through a viewing window provided in the computer as the
tape moves through a viewing section formed in the cartridge. The
lock means is provided in the cartridge for cooperating with
retaining rollers in the computer to positively and removably fix
the cartridge when inserted in the computer body, a resilient
member being provided in the cartridge for accomplishing smooth
movement of the printing tape.
Inventors: |
Murata; Minoru (Yokohama,
JA), Nishikawa; Tatsuo (Tachikawa, JA),
Hanagata; Takayoshi (Yokohama, JA) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JA)
|
Family
ID: |
26370351 |
Appl.
No.: |
05/132,057 |
Filed: |
April 7, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Apr 13, 1970 [JA] |
|
|
45-31840 |
Apr 13, 1970 [JA] |
|
|
45-31844 |
|
Current U.S.
Class: |
400/613; 400/611;
400/617; 400/173; 400/615.2; 400/618; 400/641 |
Current CPC
Class: |
G06C
11/12 (20130101) |
Current International
Class: |
G06C
11/00 (20060101); G06C 11/12 (20060101); B41j
015/00 () |
Field of
Search: |
;197/133R,133T,151,172,175,168 ;95/4,5
;274/1R,1G,4R,4B,4C,4D,4E,11R,11F,11B,11C,11D,11E |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,128,908 |
|
Sep 1956 |
|
FR |
|
1,208,748 |
|
Jan 1966 |
|
DT |
|
247,455 |
|
Dec 1947 |
|
CH |
|
262,174 |
|
Sep 1949 |
|
CH |
|
Primary Examiner: Wright, Jr.; Ernest T.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
We claim:
1. A tape cartridge comprising:
a printing tape wound in a roll for unwinding in succession;
a case for housing said printing tape therein;
holding means in said case for holding said roll of printing
tape;
a tape advancing path in said case for advancing said printing tape
unwound from said roll within said case;
a printing section in said case in said tape advancing path to
effect printing on said printing tape sequentially in the
lengthwise direction of said printing tape in accordance with the
advancement of said printing tape by an externally provided
printing device;
a visual observing section in a portion of said case downstream of
said printing section with respect to the advancing direction of
said printing tape in the tape advancing path for observing a
plurality of prints on said printing tape printed at said printing
section at a time in accordance with the advancement of said
printing tape; and
a tape discharging portion at the end of said tape advancing path
for discharging the printing tape passing through said visual
observing section out of said case.
2. A tape cartridge according to claim 1, wherein said printing
section comprises a cut-away portion provided in said case.
3. A tape cartridge according to claim 1, wherein said tape
cartridge further comprises means for changing the angle of
advancement of said printing tape with the aid of a tape angle
changing member provided in a portion of the path of said printing
tape upstream of said visual observing section, thereby inclining
said printing tape as said printing tape advances through said
visual observing section.
4. A tape cartridge according to claim 3, wherein said visual
observing section of said tape cartridge is provided with an
inclination approximately in parallel with the inclination of said
printing tape corresponding to said tape angle changing member.
5. A tape cartridge according to claim 1, wherein said tape
cartridge comprises a projection having two side edge portions
disposed on the outer surface of said case, and wherein one of said
side edge portions converges in one direction and the other side
edge portion converges in the direction opposite to said one
direction.
6. A tape cartridge according to claim 1, wherein said tape
cartridge comprises a resilient member disposed along at least a
portion of the tape advancing path of said printing tape from said
roll, said resilient member having at least one end for resiliently
bearing against said printing tape to absorb a tension in said
printing tape.
7. A tape cartridge according to claim 6, wherein said resilient
member has another end positioned in the vicinity of said printing
tape passing through said visual observing section and has a roller
at said another end.
8. A tape cartridge according to claim 6, wherein said one end of
said resilient member resiliently bearing against said printing
tape is formed into an arcuate shape.
9. A tape cartridge according to claim 6, wherein said tape
cartridge further comprises at least two holding members formed in
a position of said case for holding said resilient member.
10. A tape cartridge according to claim 2, wherein said printing
section includes pressing means for continuously pressing said
printing tape from inside said case toward the outside of said
case.
11. A tape cartridge according to claim 3, wherein said tape
cartridge further comprises a second tape angle changing member
provided between said visual observing section and said tape
discharging portion.
12. A tape cartridge according to claim 11, wherein said second
tape angle changing member includes means for restoring the changed
tape running angle substantially to the original angle.
13. A tape cartridge according to claim 11, wherein said tape
cartridge further comprises a nip means for nipping the tape
discharged with a roller mounted exteriorly of said tape cartridge
at said tape discharging portion.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a tape cartridge for use with an
electronic computer, and more particularly to a tape cartridge
removably inserted in an electronic computer and containing therein
a tape on which digits and results of operations are printed in
accordance with signals from the computer so that such information
may be displayed through a display section while the tape is
moved.
2. Description of the Prior Art
In compact electronic computers such as desk-set computers, digits
entered and results of operations have usually been displayed by a
system using a row of numerical display tubes disposed in a portion
of the computer body and selectively turned on in accordance with
the digits entered or the results of operations effected, but such
a display system has not been useful to keep the displayed records
for future use.
To overcome such a disadvantage, it has been proposed to provide a
computer body with a mechanism for holding a roll of paper, a
mechanism for feeding the paper, and a printing mechanism for
printing digits and symbols on the paper fed by the paper feeding
mechanism so that those digits and symbols printed on the paper may
be read. The described system using such paper for printing the
output of a computer has become widely used because of its
advantage that the paper carrying printed information thereon can
be directly used as means for checking or storing the results of
the calculations effected, but it has required much time for
setting the printing paper to the computer body and often involved
certain dangers. More particularly, a roll of paper to be printed
must be fixed in a predetermined position with its leading edge
nipped between feed rollers, and if the printing system in use is
of an electric discharge type, means such as a discharge circuit
supplied with a high voltage which might be dangerous to the human
body is provided adjacent to the feed path of the paper. The term
"printing" used herein includes not only the ordinary type of
printing whereby characters are imprinted under pressure on paper
but also other types of printing such as the discharge printing
which uses a discharge stylus adapted to scan discharge destroying
paper for selective discharge to thereby represent any desired
pattern on the paper or the thermal printing which uses heating
elements selectively driven to print any desired pattern.
The above-noted disadvantages peculiar to the prior art may be
overcome by a tape cartridge provided according to the present
invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to accommodate a tape of
printing paper within a cartridge and readily enable such paper to
be set with respect to a computer body.
It is another object of the present invention to provide printing
means and reading means in the path of said printing paper moving
in the cartridge to thereby enable information printed on the paper
to be read from outside the cartridge.
It is still another object of the present invention to provide a
cartridge in which the paper tape may be inclined as it moves
through the reading means, thereby enabling the information on the
tape to be readily read.
It is yet another object of the present invention to provide lock
means in the cartridge for correctly and removably fixing the
cartridge to a computer body.
It is still another object of the present invention to provide
retaining means in a computer body for cooperating with said lock
means to effectively fix the cartridge to the computer body.
It is still another object of the present invention to provide a
cartridge having a resilient member for accomplishing smooth
movement of the tape.
These and other objects and advantages of the present invention
will become fully apparent from the following description of
embodiments thereof taken in conjunction with the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a compact electronic computer and a
tape cartridge containing therein a printing tape to be set to the
computer.
FIG. 2 is a perspective view of the tape cartridge for illustrating
the interior thereof in greater detail.
FIG. 3 is an exploded perspective view of the cartridge shown in
FIG. 2.
FIGS. 4(a) to 4(d) illustrate an angle changing member used for
inclining the tape.
FIG. 5 is a perspective view showing the bottom of the
cartridge.
FIG. 6 is a fragmentary perspective view of the computer for
illustrating retaining means provided in the computer body for
retaining the cartridge thereto.
FIG. 7 is a bottom plan view of the computer body for further
illustrating lock means provided therein for cooperating with the
retaining means of FIG. 6 to fix the cartridge to the computer.
FIGS. 8(a) and 8(b) illustrate the manner in which the cartridge is
retained by cooperation between the retaining means of FIG. 6 and
the lock means of FIG. 7.
FIG. 9 is a perspective view of the tape driving system.
FIG. 10 is an exploded perspective view for illustrating the
plunger portion of the driving system.
FIG. 11 is a side view of the driving system.
FIG. 12 is a vertical sectional view of the driving sytem of FIG.
11.
FIG. 13 is a vertical sectional view of the tape feed
mechanism.
FIGS. 14(a) and 14(b) are cross sectional views of the tape driving
roller taken along section line 14--14 of FIG. 13.
FIG. 15 is a cross-sectional view taken along section line 15--15
of FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown a computer body generally
designated by 11 and a tape cartridge generally designated by 12
which is to be inserted into the computer body 11. The computer
body 11 accommodates therein various circuits (not shown) such as
digit entering circuit, operating circuit, display circuit, etc.
and can perform as an independent computer. In the forward upper
surface of the computer body 11 there are provided digit entering
keys 13 for entering digital data and function keys 14 for
effecting various calculations on such digital data. The tape
cartridge 12 contains therein a roll 25 (FIG. 2) of narrow tape
strip 17 wound in the form of a coil and rotatably held so as to be
freely unwound. The cartridge 12 has a recess 15 and a viewing
section 16 both formed in the front end thereof so that tape 17
unwound from said roll 25 may be imprinted with characters at the
front recess 15 by a thermal head or printing means 42 (FIG. 6)
provided in a portion of the computer body 11 corresponding to the
recess 15 as will be described later, and then guided through the
viewing section 16 which is generally sloped, preferably at
45.degree., to enable the information printed on the moving tape to
be readily read from outside the cartridge 12. A viewing window 18
is provided in a portion of the computer body 11 corresponding to
the viewing section 16 of the tape cartridge 12 so that when the
cartridge 12 is inserted into the computer body 11 the digital
information on the tape 17 moving through the viewing section 16
may be viewed from outside the computer body 11. The viewing window
18 of the computer body 11 is also sloped complementarily to the
viewing section 16 of the cartridge 12 so as to facilitate the read
out of the printed information on the tape 17.
It will thus be seen that the above-described computer is not of
the type which has a fixed display means but of the type in which a
tape 17 imprinted with information is moved in the cartridge 12 so
that information on the tape may be read as it runs along its path
of movement and thus preservation of such tape 17 provides
preservation of the results of calculations effected by the
computer. Moreover, the tape setting may be accomplished simply by
inserting the cartridge 12 into the computer body 11.
FIGS. 2 and 3 illustrate the tape cartridge 12 in greater detail.
As shown, the tape cartridge 12 comprises a bottom member 19 and a
top cover 20 both formed of a material such as plastic or the like.
The bottom member 19 includes a bottom plate 21 and three side
plates 22, 23 and 24. Substantially in the center of the bottom
plate 21 there is formed a core 26 for rotatably holding thereon a
tape roll 25 from which the tape 17 may be freely supplied. A
resilient member 27 to be described may be fixedly held in the
bottom member 19 by holder members 28 and 29 formed therein, and a
keep member 30 also to be described may be held in the bottom
member 19 by holder members 31 and 32 formed therein.
The resilient member 27 generally takes a U-shaped configuration,
and one end thereof forms a U-shaped portion 33 for bearing against
the tape 17, while the other end carries a rotatable roller 34 to
provide a tape feeder portion cooperable with a drive roller 49
(FIG. 6) to be described.
The tape cartridge 12 is such that when the printing tape 17 is
driven to effect printing or display of prints by the drive roller
49 in the direction as indicated by an arrow C in FIG. 2, the tape
17 is taut and the shock absorbing portion 27' of the resilient
member 27 flexes inwardly toward the tape roll 25. In other words,
since the inertia of the tape roll 25 due to its mass is great as
compared with the drive of the tape 17, the tape roll 25 itself is
not substantially rotated and the drive of the tape 17 is absorbed
by the shock absorbing portion 27'. Subsequently, the tape 17 roll
25 is rotated by the return force of the flexed shock absorbing
portion 27' as it returns to its normal position so as to provide a
sufficient slack of the tape 17 for a next printing process.
Thereafter, the tape 17 is again subjected to a drive and moved to
allow a printing and display of the print to take place, thus
gradually increasing its tension to thereby flex the shock
absorbing portion 27' again. When the drive to the tape 17 is
stopped, the flexed shock absorbing portion 27' again returns to
its normal position to allow the rotation of the tape roll 25. By
repeating the described operation, smooth and intermittent tape
feed may be accomplished at high speeds.
The keep member 30 has a pad 35 of felt or like material attached
to one end thereof which is mounted adjacent the printing device 42
(FIG. 6) provided in the computer body 11, and this keep member 30
is provided so that the heat retaining characteristic of the felt
pad 35 thereof may help to retain heat in the heatsensitive tape 17
at a portion thereof to be printed prior to the printing process,
thereby increasing the print sensitivity or responsiveness of the
tape 17 so as to ensure printing is effected on the tape 17 as well
as to ensure the movement of the tape 17 through the viewing
section 16. The felt pad 35 of such heat retaining characteristic
is also useful to greatly increase the service life or durability
of the thermal printing head 42, FIG. 6.
The top cover 20 includes a top plate 36, a transparent front end
plate 37 forming the viewing section 16, and an angle changing
member 38 depending from the top plate 36, the front end plate 37
and angle changing member 38 being both inclined substantially at
45.degree. with respect to the bottom plate 21. Between the front
end plate 37 and the angle changing member 38 there is formed a
cut-away 39.
Numeral 40 designates a low friction sheet formed of Teflon (trade
name) to be interposed between the tape roll 25 and the bottom
plate 21 so as to facilitate the rotation of the tape roll 25.
Numeral 41 designates a conically shaped angle changing member
depending from the top plate 36 for changing the angle at which the
tape 17 moves.
To assemble the parts of FIG. 3 into the complete tape cartridge 12
as shown in FIG. 2, the low friction sheet 40 is first inserted
over the core 26 in the bottom plate 21, and then the tape roll 25
is inserted similarly in superposed relationship on the sheet 40.
The resilient member 27 is fixed to the holder members 28 and 29,
while the keep member 30 is fixed to the holder members 31 and 32
at an angle approximately equal to that of the front end plate 37.
Thereafter, the top cover 20 is fixed to the bottom member 19 with
the pad 35 of the keep member 30 positioned in the cut-away 39
formed in the upper cover 20. There is thus provided a tape
cartridge assembly 12.
In such a tape cartridge 12, the tape 17 unwound from the tape roll
25 has its direction of movement changed by the U-shaped portion 33
of the resilient member 27 so as to be guided along the member 27
and then led out of the cartridge 12 between the side wall 24 and
the angle changing member 38 to change its direction of movement so
as to pass through the cartridge 12 between the keep member 30 and
the front end plate 37. Thus, the tape 17 moves between the keep
member 30 and the front end plate while keeping an angle of about
45.degree. with respect to the bottom plate 21. In other words, the
tape 17 has its printing surface somewhat inclined upwardly as it
passes through the viewing section 16. Such inclined position of
the printing surface in the viewing section 16 is greatly useful to
facilitate the read out of the printed information on the tape
17.
As noted above, the resilient member 27 bears against the tape 17
as the latter is unwound from the supply roll 25, and therefore,
when the tape 17 is intermittently driven to move, a tension
sharply developing in such driven tape 17 will be absorbed by the
resilient member 27, which will thus flex inwardly to prevent any
excessive force from being imparted to the tape 17 and enable very
smooth feed of the tape 17.
FIGS. 4(a) - 4(d) further illustrate the angle at which the tape 17
is moved in the described manner. FIGS. 4(a) and 4(b) are front and
right side views, respectively, of the angle changing member 38. If
the angle changing member 38 forms an angle of approximately
45.degree., for example, with respect to the bottom plate 21 as
shown in FIG. 4(b), one side edge 38' of the member 38 will also
have an angle of approximately 45.degree. as shown in FIG. 4(a).
Thus, the angle changing member 38 serves to smoothly change the
direction of movement of the tape 17 and thereby eliminate any
danger of severing the tape 17 which would otherwise result from an
excessive force imparted to the tape 17 when it is suddenly turned
to the direction along the front end plate 37 after travelling
along the resilient member 27 while keeping its upright position
with respect to the bottom plate 21. FIGS. 4(c) and 4(d) are front
and left side views, respectively, of the conically shaped angle
changing member 41 disposed at a terminus in the path of the tape
17 for recovering the upright position of the tape 17 after it has
travelled along the front end plate 37 while keeping the angle of
45.degree. with respect to the bottom plate 21.
As described just above, the angle of the tape 17 with respect to
the bottom plate 21 is provided by the angle changing member 38
before the tape reaches the front end plate 37, then the tape 17
passes through the cut-away 39 to reach the front end plate 37. In
the cut-away 39 there is positioned the pad 35 of the keep member
30 as described previously, so that when the cartridge 12 is
inserted into the computer body 11 the tape 17 moves between the
pad 35 and a thermal head 42 comprising a column of four
selectively movable dots and a row of five selectively movable
dots. While so moving, the tape 17 is urged into contact with the
thermal head 42 by a suitable pressure so that printing may be
effected always under good conditions, and the information thus
printed on the tape 17 may be viewed from outside the cartridge 12
through the transparent front end plate 37.
As shown in FIG. 5, the underside of the cartridge 12 is
substantially flat and has a lozenge-shaped projection or retaining
member 43 formed in the forward center thereof. The retaining
member 43 serves to force the tape cartridge 12 toward the thermal
head 42 with a predetermined pressure once the cartridge 12 has
been inserted into the computer body 11. This is accomplished with
the aid of a pair of rotatable rollers 44 and 45 urged toward each
other as shown in FIG. 6. For this purpose, the computer body 11 is
formed with a channel 46 along which the projected retaining member
43 slides when the tape cartridge 12 is received into the computer
body 11, and further formed with stoppers 47 and 48 for positioning
the inserted cartridge 12 in place. As shown, the computer body 11
is provided with a tape driving roller 49 adapted to nip and drive
the tape 17 between itself and the roller 34 at one end of the
resilient member 27 disposed within the tape cartridge 12.
FIG. 7 shows a driving mechanism for the pair of rollers 44 and 45.
Two arms 50 and 51 are pivotally mounted at one end on shafts 52
and 53 and provided with retainer means 54 and 55, which are biased
toward each other by a spring 56. Secured to the other ends of the
respective arms 50 and 51 are shafts 57 and 58, on which the
rollers 44 and 45 are rotatably mounted in an opening 58'. Since
the rollers 44 and 45 are normally biased toward each other by the
spring 56, once the tape cartridge 12 is inserted into the computer
body 11, the lozenge-shaped retaining member 43 is snapped between
the rollers 44 and 45 to further push aside these two rollers 44,
45 against their closing forces as shown in FIG. 8(a) until the
apexes 59 and 60 of the lozenge-shaped retaining member 43 pass the
rollers 44 and 45 to come to a position as shown in FIG. 8(b),
whereupon the rollers 44 and 45 are caused to come toward each
other by the spring 56. Thus, the retaining member 43 and
accordingly the tape cartridge 12 is subjected to a force directed
as indicated by the solid-line arrow D. When assuming the position
as shown in FIG. 8(b), the tape cartridge 12 is restrained by the
stoppers 47 and 48 and thus retained in a position where it is
constantly urged toward the thermal head 42 or in the direction as
indicated by the dotted-line arrow E.
The removal of the tape cartridge 12 from the computer body 11 may
be accomplished by pulling back the cartridge 12 so as to displace
the retaining member 43 in the direction opposite to that indicated
by the dotted-line arrow E, FIG. 8(b) until it forcibly opens the
rollers 44 and 45 to pass therebetween and disengage therefrom.
In the illustrated example, the retaining member 43 is shown as a
lozenge shape, whereas this is not the only possible shape but the
retaining member 43 may take any other suitable shape such as
ellipse which converges in two directions so as to allow the
insertion and removal of the cartridge 12 by cooperation with the
rollers 44 and 45 in the described manner.
As noted above, the cartridge 12, once inserted in the computer
body 11, may always be urged toward the thermal head 42 with a
predetermined force by the retaining rollers 44, 45 provided in the
computer body 11, so that the tape 17 supplied from within the the
cartridge 12 may be nipped between the roller 34 and the driving
roller 49 and intermittently fed by intermittently driving the
roller 49.
Referring to FIGS. 9 to 15, the system for intermittently feeding
the tape 17 is shown in greater detail. In front of a plunger case
61 there is a rack 62 formed at the forward end portion of a
plunger actuator 63. An arm 64 for holding the rack 62 is secured
to a base plate 65. A gear 66 meshing with the rack 62 is mounted
on a main drive shaft 67 for rotation therewith. A return spring 68
is provided to normally bias the main drive shaft 67 for clockwise
rotation. An auxiliary drive shaft 69 is loosely fitted on the main
drive shaft 67 in a manner to be described, and it has a one-way
rotating mechanism mounted on its inner side wall. A driving roller
49 of rubber which has already been described is mounted around the
auxiliary drive shaft 69, and a resilient disc 70 is secured to the
main drive shaft 67, the disc 70 having spring arms 71 and 72 for
resiliently pressing followers 81 and 82 (FIGS. 14a and 14b) which
will be described later. A unit fixing plate 73 formed of a
resilient material is secured to the top of the plunger case 61 and
has fixed mounting arms 74, 75 and 76 of a U-shaped cross-section
and capable of absorbing any shock imparted thereto by the
reciprocation of the plunger actuator 63. The base plate 65 is
secured to the plunger case 61 to receive actuator 63 and carry the
driving roller 49, thereby forming a part of the tape driving
system. A shock absorbing member 77 formed of rubber or like
material is fitted to the base of the rack 62 extending from the
plunger actuator 63, so as to absorb the shock imparted by the
actuator 63 when it is returned by the force of the spring 68 and
strikes the holding arm 64.
As shown in FIG. 14(a), a cam 78 is formed below the resilient disc
70 and at the upper end of the main drive shaft 67. The cam 78 is
formed with cam portions 79 and 80 for receiving therein
cylindrical followers 81 and 82 respectively. The spring arms 71
and 72 formed in the resilient disc 70 bear against the cylindrical
surfaces of the respective followers 81 and 82 to bias these
followers 81, 82 toward the inner side wall 83 of the auxiliary
drive shaft 69. Thus, when the main drive shaft 67 is rotated in
the direction indicated by arrow A to drive the cam 78 to rotate in
the same direction, the followers 81 and 82 will be trapped in the
wedge-shaped spaces defined between the cam portions 79, 80 and the
inner wall 83 of the auxiliary drive shaft 69 to rotate this shaft
69 also in the direction of the arrow A. If the main drive shaft 67
is rotated in the direction opposite to that indicated by the arrow
A, the cam 78 will also be rotated in such opposite direction to
cause the spring arms 71 and 72 to follow the rotation of the cam
78, whereby the spring arms 71 and 72 will force the followers 81
and 82 to follow only the cam 78 along the cam portions 79 and 80,
thus releasing the operative engagement between the main and
auxiliary drive shafts 67 and 69 (See FIG. 14(b). The auxiliary
drive shaft 69 is further formed with an intermediate wall surface
83, beneath which is disposed a cam 86 loosely fitted
concentrically with the main drive shaft 67 and fixed to the base
plate 65 by means of screws 84 and 85.
The cam 86 has two symmetrical cam portions 87 and 88 similarly to
the cam 78, and cylindrical followers 89 and 90 are received in
these cam portions 87 and 88 respectively. When the cam 86 is fixed
to the base plate 65, a resilient pressure plate 91 (FIG. 13)
similar in shape to the resilient disc 70 is fixed integrally to
the fixed base of the cam 86 and the followers 89 and 90 are
resiliently pressed by spring aims 92 and 93 in the same way as the
followers 81 and 82, as shown in FIG. 15. Therefore, when the cam
78 on the main drive shaft 67 is rotated in the direction of arrow
A, the auxiliary drive shaft 69 will also be rotated in the same
direction so that the followers 89 and 90 in the cam 86 secured to
the underside of the cam 78 are rotated within the inner wall of
the auxiliary drive shaft 69 and forced out of the wedge-shaped
spaces defined by the inner wall of the auxiliary drive shaft 69
and the cam portions 87, 88 of the cam 86 so as to bear against the
spring arms 92 and 93. In this way, the rotation of the main drive
shaft 67 in the direction of arrow A may be transmitted to the
auxiliary drive shaft 69.
When the main drive shaft 67 is rotated in the direction or arrow B
opposite to the direction of arrow A, the auxiliary drive shaft 69
is prevented from following the rotation of the cam 78 because the
followers 89 and 90 therebelow are then trapped in the wedge-shaped
spaces defined by the cam portion 87 and 88 of the cam 86 and the
inner wall of the auxiliary drive shaft 69, which is thus immovably
fixed to the cam 86 by the followers 89 and 90. On the other hand,
the cam 78 and accordingly the main drive shaft 67 may be rotated
while the spring arms 71 and 72 thereof are pressing the followers
81 and 82.
It will thus be appreciated that the different pairs of followers
81, 82 and 89, 90 resiliently pressed in the same direction allow
the auxiliary drive shaft 69 to rotate only in the direction of
arrow A in response to the reciprocal rotation of the main drive
shaft 67, but the rotation of the auxiliary drive shaft 69 in the
direction of arrow B opposite to the direction of arrow A is
prevented due to the followers 89, 90 trapped in the wedge-shaped
spaces.
In using the above-described cartridge 12 with the computer body
11, the tape 17 is initially drawn to the exposed roller 34 arms
then the cartridge 12 is inserted into the cartridge receiving
portion in the computer body 11, whereby the retaining member 43 at
the bottom of the cartridge 12 is nipped between the pair of
rollers 44, 45 and forced toward the printing head 42 (FIG. 6) at a
predetermined pressure until the tape portion exposed at the
cut-away 39 is brought into intimate contact with the printing head
42 while the leading edge of the tape 17 is nipped between the
roller 34 and the driving roller 49.
If an operator closes a conventional power switch (not shown) and
depresses desired digit entering keys 13 and function keys 14 to
effect an operation, the entered digits and the result of the
operation will be applied one by one to the printing head 42
through a conventional operating circuit (not shown).
In response thereto, an operating current flows into the plunger in
the tape driving system so that the actuator 63 is attracted
against the force of the spring 68 in the direction as indicated by
arrow P in FIG. 12. As a result, the gear 66 is rotated
counter-clockwise to cause the main drive shaft 67 to rotate in the
direction of arrow A. As described above, such rotation of the main
drive shaft 67 in the direction of arrow A causes the auxiliary
drive shaft 69 to be rotated in the same direction due to the
followers 81 and 82 being then trapped in the wedge-shaped spaces
defined by the cam 78 and the inner wall of the auxiliary drive
shaft 69, so that the printing tape 17 in the cartridge 12 is
driven to move only a distance corresponding to one impressed
character. Subsequently, when a printing current flows into the
thermal head 42, the plunger operating current is cut off to allow
the actuator 63 to be returned in the direction opposite to the
direction of arrow P by the return spring 68 wound around the main
drive shaft 67. The actuator 63 strikes the end of the rack holding
arm 64, but the shock arising therefrom is absorbed by the shock
absorber 77 fitted to the actuator 63 and the resilient U-shaped
arms 74-76.
For the return movement of the actuator 63 or the reverse rotation
of the main drive shaft 67 in the direction opposite to the
direction of arrow A, the auxiliary drive shaft 69 is prevented
from rotating by the cooperation between the cam 86 and associated
followers 89, 90, resulting in idle rotation of the main drive
shaft 67 and no movement of the tape 17.
In this way, the tape driving system drives to move the tape 17 a
distance corresponding to one impressed character each time
printing is effected by the printing head 42.
Thus, the data printed successively on the tape 17 are moved to
reach the viewing section 16 of the cartridge 12 so that the
information representing the entered digits and the results of the
effected calculations can be read through the viewing window 18
provided in the computer body 11.
* * * * *